Compressor and correct CFM for paint spraying?
Discussion
I'd quite like to give this a go on my race cars and have been Googling for information, but I keep seeing wildly varying accounts of what kind of CFM you need a compressor to give for good paint spraying.
Can anyone with practical experience advise of the sort of kit required to get started? I'm not looking for a professional quality job at this moment, I'm looking for the things I need to be capable of an adequate job for a track car.
Can anyone with practical experience advise of the sort of kit required to get started? I'm not looking for a professional quality job at this moment, I'm looking for the things I need to be capable of an adequate job for a track car.
The gun type is probably more important. It's the volume they consume that counts so if you're only doing a panel at a time then you don't need a big compressor. For example a full size gun such as my Devilbiss HVLP just needs 30 PSI inlet pressure and sprays at 10 PSI at the air cap but it consumes 13 CFM. I also have a toch up gun which uses the same pressure but consumes 8 CFM.
You can buy LVLP guns which use around 4-5 CFM but you're unlikely to get as good a finish. If you're thinking of doing an entire car then you'll need a big compressor without a doubt.
You can buy LVLP guns which use around 4-5 CFM but you're unlikely to get as good a finish. If you're thinking of doing an entire car then you'll need a big compressor without a doubt.
GTVOX said:
The gun type is probably more important. It's the volume they consume that counts so if you're only doing a panel at a time then you don't need a big compressor. For example a full size gun such as my Devilbiss HVLP just needs 30 PSI inlet pressure and sprays at 10 PSI at the air cap but it consumes 13 CFM. I also have a toch up gun which uses the same pressure but consumes 8 CFM.
You can buy LVLP guns which use around 4-5 CFM but you're unlikely to get as good a finish. If you're thinking of doing an entire car then you'll need a big compressor without a doubt.
This is the sort of info I'm after, so thank you. You can buy LVLP guns which use around 4-5 CFM but you're unlikely to get as good a finish. If you're thinking of doing an entire car then you'll need a big compressor without a doubt.
The gun CFM, should it be matched to the lower value CFM of the compressor or the higher one? I've forgotten what the term was now... But it seemed there was a headline figure about a third higher than the constant figure when I was reading up last week.
Small compressors are usually advertised showing their air displacement figure, not the important one which is 'free air delivery'.
FAD is usually around 1/2 to 2/3 of the displacement figure.
Makes the small ones look far more capable than they really are & AFAIAC is a bit of a con.
Bear in mind also with small ones that the the 100+ psi figure shown is the pressure at which the compressor will usually cut out as the tank is full.
It does not mean that it can deliver (let's say) the advertised 8cfm AND maintain it at 100+psi.
So many who buy one & try an impact wrench or air sander are left wondering why they won't work.
FWIW I SMART repair with small HVLP gravity feed guns (0.8 & 1.0 air caps) with a 2hp 50 litre compressor. It's fine with those.
I also have a cheapie full size HVLP gravity feed gun (1.4 air cap). It will work with it for basecoat & clearcoat but it's working its b
ks off so not ideal & I don't use it for work.
Friend of mine has a 3hp & that does the job fine but you're at the top end of single phase domestic electrics & even then it really needs to be on a cooker size circuit.
He also runs an air sander off it.
FAD is usually around 1/2 to 2/3 of the displacement figure.
Makes the small ones look far more capable than they really are & AFAIAC is a bit of a con.
Bear in mind also with small ones that the the 100+ psi figure shown is the pressure at which the compressor will usually cut out as the tank is full.
It does not mean that it can deliver (let's say) the advertised 8cfm AND maintain it at 100+psi.
So many who buy one & try an impact wrench or air sander are left wondering why they won't work.
FWIW I SMART repair with small HVLP gravity feed guns (0.8 & 1.0 air caps) with a 2hp 50 litre compressor. It's fine with those.
I also have a cheapie full size HVLP gravity feed gun (1.4 air cap). It will work with it for basecoat & clearcoat but it's working its b
ks off so not ideal & I don't use it for work.Friend of mine has a 3hp & that does the job fine but you're at the top end of single phase domestic electrics & even then it really needs to be on a cooker size circuit.
He also runs an air sander off it.
Edited by paintman on Tuesday 21st January 17:29
paintman said:
Small compressors are usually advertised showing their air displacement figure, not the important one which is 'free air delivery'.
FAD is usually around 1/2 to 2/3 of the displacement figure.
Makes the small ones look far more capable than they really are & AFAIAC is a bit of a con.
Bear in mind also with small ones that the the 100+ psi figure shown is the pressure at which the compressor will usually cut out as the tank is full.
It does not mean that it can deliver (let's say) the advertised 8cfm AND maintain it at 100+psi.
So many who buy one & try an impact wrench or air sander are left wondering why they won't work.
FWIW I SMART repair with small HVLP gravity feed guns (0.8 & 1.0 air caps) with a 2hp 50 litre compressor. It's fine with those.
I also have a cheapie full size HVLP gravity feed gun (1.4 air cap). It will work with it for basecoat & clearcoat but it's working its bks off so not ideal & I don't use it for work.
Friend of mine has a 3hp & that does the job fine but you're at the top end of single phase domestic electrics & even then it really needs to be on a cooker size circuit.
He also runs an air sander off it.
Good Post, thank you. Can you recommend any guns for a beginner that will be capable of achieving a decent finish? I'll likely be looking for a 3hp 100litre job I think. FAD was the figure I couldn't remember the name of! FAD is usually around 1/2 to 2/3 of the displacement figure.
Makes the small ones look far more capable than they really are & AFAIAC is a bit of a con.
Bear in mind also with small ones that the the 100+ psi figure shown is the pressure at which the compressor will usually cut out as the tank is full.
It does not mean that it can deliver (let's say) the advertised 8cfm AND maintain it at 100+psi.
So many who buy one & try an impact wrench or air sander are left wondering why they won't work.
FWIW I SMART repair with small HVLP gravity feed guns (0.8 & 1.0 air caps) with a 2hp 50 litre compressor. It's fine with those.
I also have a cheapie full size HVLP gravity feed gun (1.4 air cap). It will work with it for basecoat & clearcoat but it's working its b
ks off so not ideal & I don't use it for work.Friend of mine has a 3hp & that does the job fine but you're at the top end of single phase domestic electrics & even then it really needs to be on a cooker size circuit.
He also runs an air sander off it.
Edited by paintman on Tuesday 21st January 17:29
Very much a case of getting what you pay for.
My mini HVLP guns are Anest Iwata but they're £200+ each. Iwata also do full size guns.
Other big names are Sata & Devilbiss.
The miniguns are intended for small areas & definitely not for bonnet, roof or other large panels.
I suggest you look at full size guns.
Buying used is risky - discontinued models may have worn out fluid tips & if spares (which aren't cheap!) are no longer available then you have a problem.
You will need a moisture separator.
Don't get one of the type that also has an oiler. Oilers are not used with sprayguns!
My mini HVLP guns are Anest Iwata but they're £200+ each. Iwata also do full size guns.
Other big names are Sata & Devilbiss.
The miniguns are intended for small areas & definitely not for bonnet, roof or other large panels.
I suggest you look at full size guns.
Buying used is risky - discontinued models may have worn out fluid tips & if spares (which aren't cheap!) are no longer available then you have a problem.
You will need a moisture separator.
Don't get one of the type that also has an oiler. Oilers are not used with sprayguns!
Edited by paintman on Tuesday 21st January 23:06
V8covin said:
Devilbiss flg5 is a great budget gun,get the 1.4 for basecoat and clear
Cheers, thank you. The moisture filter, is that something that attaches to the gun or the compressor itself somewhere? And was the oiler comment referring to the moisture separator or the compressor itself?
Combined water separator & pressure regulator:
https://www.ebay.co.uk/itm/1-4-BSP-Air-Line-Filter...
This is the separator & oiler that you don't want. Used with air tools that require lubrication, some of the oil being passed down the airline to the tool. Must not be used with spraying equipment incl airline:
https://www.ebay.co.uk/itm/Air-Compressor-Oil-Lubr...
Get one of these for each gun. Attach to the bottom of the gun. Use to set pressure at the gun, far more accurate as it will take into account pressure drop in the airline:
https://www.ebay.co.uk/itm/On-Gun-Air-Pressure-Reg...
All the above are just to let you see the sort of thing you need & aren't a recommendation!
You will need the appropriate male tails to fit the female connectors on the compressor & the airline. Use PTFE tape to seal the threads.
https://www.ebay.co.uk/itm/1-4-BSP-Air-Line-Filter...
This is the separator & oiler that you don't want. Used with air tools that require lubrication, some of the oil being passed down the airline to the tool. Must not be used with spraying equipment incl airline:
https://www.ebay.co.uk/itm/Air-Compressor-Oil-Lubr...
Get one of these for each gun. Attach to the bottom of the gun. Use to set pressure at the gun, far more accurate as it will take into account pressure drop in the airline:
https://www.ebay.co.uk/itm/On-Gun-Air-Pressure-Reg...
All the above are just to let you see the sort of thing you need & aren't a recommendation!
You will need the appropriate male tails to fit the female connectors on the compressor & the airline. Use PTFE tape to seal the threads.
Gassing Station | Bodywork & Detailing | Top of Page | What's New | My Stuff